Linux The Comprehensive Guide (Michael Kofler) (Z-Library)

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Michael Kofler Linux The Comprehensive Guide

Imprint This e-book is a publication many contributed to, specifically: Editor Meagan White Acquisitions Editor Hareem Shafi German Edition Editor Christoph Meister Translation Winema Language Services, Inc. Copyeditor Melinda Rankin Cover Design Graham Geary Photo Credit Shutterstock: 1929493523/© Dennis Stogsdill, 2048513402/© Andrey Suslov Layout Design Vera Brauner Production E-Book Kelly O’Callaghan Typesetting E-Book SatzPro, Germany We hope that you liked this e-book. Please share your feedback with us and read the Service Pages to find out how to contact us. The Library of Congress has cataloged the printed edition as follows: Names: Kofler, Michael, author. Title: Linux : the comprehensive guide / by Michael Kofler. Other titles: Linux (Rheinwerk Publishing). English Description: 1st edition. | Bonn ; Boston : Rheinwerk Publishing, 2024. | Translated from German. Identifiers: LCCN 2024009863 | ISBN 9781493224999 (paperback) | ISBN 9781493225002 (ebook) Subjects: LCSH: Linux. | Operating systems (Computers) Classification: LCC QA76.774.L46 K6413 2024 | DDC 005.4/46--dc23/eng/20240328 LC record available at https://lccn.loc.gov/2024009863 ISBN 978-1-4932-2499-9 (print) ISBN 978-1-4932-2500-2 (e-book) ISBN 978-1-4932-2501-9 (print and e-book) © 2024 by Rheinwerk Publishing, Inc., Boston (MA) 1st edition 2024 1st German edition published 2023 by Rheinwerk Verlag, Bonn, Germany

Contents Preface ............................................................................................................................... 31 PART I Installation 1 What Is Linux? 37 1.1 Introduction ..................................................................................................... 37 1.2 Hardware Support ......................................................................................... 38 1.3 Distributions .................................................................................................... 39 1.3.1 Common Linux Distributions ..................................................... 41 1.4 Open-Source Licenses (GPL and Company) ........................................ 44 1.4.1 Licensing Conflicts between Open- and Closed-Source Software ............................................................... 46 1.5 The History of Linux ..................................................................................... 46 2 Installation Basics 49 2.1 Requirements .................................................................................................. 49 2.2 BIOS and EFI ..................................................................................................... 50 2.2.1 EFI System Partition ....................................................................... 51 2.2.2 UEFI Secure Boot ............................................................................. 51 2.3 Installation Variants ..................................................................................... 53 2.3.1 Installation Medium ...................................................................... 53 2.3.2 Network Installation ..................................................................... 54 2.3.3 Installation Program ...................................................................... 54 2.3.4 Installation Location ...................................................................... 55 2.4 Overview of the Installation Process .................................................... 56 2.5 Partitioning Basics ........................................................................................ 58 2.5.1 MBR Basics ........................................................................................ 59 2.5.2 GPT Basics ......................................................................................... 59 2.5.3 Partition Names .............................................................................. 60 2.5.4 File Systems ...................................................................................... 617

Contents2.6 LVM and Encryption ...................................................................................... 61 2.6.1 Logical Volume Manager .............................................................. 61 2.6.2 Encryption ......................................................................................... 62 2.6.3 Limitations ........................................................................................ 63 2.6.4 Recommendation ........................................................................... 63 2.7 Creating Linux Partitions ............................................................................ 64 2.7.1 Number and Size of Linux Partitions ........................................ 65 2.7.2 Which File System? ......................................................................... 67 2.8 Setting the Scope of the Installation .................................................... 68 2.9 Basic Configuration ....................................................................................... 68 2.10 System Changes, Extensions, and Updates ........................................ 70 2.10.1 Software Installation and Package Management ............... 70 2.10.2 Updates .............................................................................................. 70 2.10.3 Configuration ................................................................................... 72 3 Installation Instructions 75 3.1 Debian ................................................................................................................. 76 3.1.1 Installing Debian ............................................................................. 78 3.1.2 Live-Image Installation .................................................................. 78 3.1.3 Standard Installation ..................................................................... 80 3.1.4 Getting Started ................................................................................ 83 3.2 Fedora .................................................................................................................. 84 3.2.1 Installing Fedora .............................................................................. 86 3.2.2 Getting Started ................................................................................ 90 3.3 Linux Mint ......................................................................................................... 92 3.4 Manjaro Linux .................................................................................................. 95 3.5 openSUSE ........................................................................................................... 98 3.5.1 Installing openSUSE ....................................................................... 100 3.5.2 Getting Started ................................................................................ 103 3.6 Pop!_OS .............................................................................................................. 104 3.6.1 Installing Pop!_OS .......................................................................... 105 3.6.2 Getting Started ................................................................................ 107 3.7 Ubuntu ................................................................................................................ 108 3.7.1 Installing Ubuntu ............................................................................ 110 3.7.2 Getting Started ................................................................................ 1148

ContentsPART II Using Linux 4 GNOME 119 4.1 Personal Assessment ................................................................................... 120 4.2 Getting Started ............................................................................................... 121 4.2.1 Panel ................................................................................................... 121 4.2.2 Activities ............................................................................................ 122 4.2.3 Dock (Dash) ...................................................................................... 124 4.2.4 Running Programs ......................................................................... 124 4.2.5 Special Features of Keyboard, Mouse, and Touchpad ........ 126 4.2.6 Using the Clipboard Efficiently .................................................. 128 4.3 File Manager .................................................................................................... 128 4.3.1 Operation .......................................................................................... 129 4.3.2 Removable Media ........................................................................... 132 4.3.3 Access to Network Directories ................................................... 133 4.3.4 Sharing Network Directories ...................................................... 134 4.3.5 Plugins ................................................................................................ 137 4.3.6 Additional Programs ...................................................................... 137 4.4 System Configuration .................................................................................. 138 4.4.1 Mouse, Touchpad, and Keyboard .............................................. 139 4.4.2 Network Configuration ................................................................ 141 4.4.3 Online Accounts .............................................................................. 141 4.4.4 Printers ............................................................................................... 141 4.4.5 Monitor and Projector Configuration ...................................... 143 4.4.6 High DPI Displays ........................................................................... 144 4.4.7 Colors .................................................................................................. 145 4.4.8 User Administration ...................................................................... 145 4.4.9 Software Installation and Updates .......................................... 146 4.4.10 Remote Maintenance .................................................................... 147 4.5 Fonts .................................................................................................................... 148 4.6 GNOME Tweak Tool ...................................................................................... 150 4.7 GNOME Shell Extensions ............................................................................ 152 4.7.1 Useful Extensions ........................................................................... 154 4.7.2 Tips and Tricks ................................................................................. 155 4.8 GNOME Shell Themes .................................................................................. 156 4.9 Internal Details of GNOME ........................................................................ 156 4.9.1 XDG Directories and Scripts ........................................................ 158 4.10 GNOME Classic ................................................................................................ 1599

Contents5 KDE 161 5.1 Basic Principles ................................................................................................ 161 5.1.1 Terminology ...................................................................................... 162 5.1.2 Distributions ..................................................................................... 162 5.2 Operation ........................................................................................................... 163 5.2.1 Important Plasmoids ..................................................................... 166 5.3 File Manager ..................................................................................................... 167 5.3.1 Renaming Files (KRename) .......................................................... 169 5.3.2 External Media and Network Directories ............................... 170 5.4 KDE Configuration ......................................................................................... 170 PART III Linux Basics 6 Using the Terminal 179 6.1 Text Consoles and Terminal Windows ................................................. 179 6.1.1 Terminal Window ........................................................................... 181 6.1.2 Running Commands ...................................................................... 184 6.2 Displaying and Editing Text Files ............................................................ 185 6.2.1 Text Editors ....................................................................................... 186 6.3 man and info .................................................................................................... 189 7 Bash (Shell) 193 7.1 What Is a Shell? ............................................................................................... 193 7.1.1 Other Shells ....................................................................................... 194 7.2 Configuration ................................................................................................... 195 7.3 Command Input .............................................................................................. 198 7.3.1 Expanding Command and File Names .................................... 198 7.3.2 Important Keyboard Shortcuts ................................................... 200 7.3.3 Alias Abbreviations ......................................................................... 201 7.4 Input and Output Redirection .................................................................. 202 7.4.1 Output Multiplication Using tee ............................................... 205 7.5 Executing Commands .................................................................................. 20510

Contents7.6 Globbing and Substitution/Expansion ................................................ 208 7.6.1 Command Substitution ................................................................ 211 7.6.2 Single versus Double Quotation Marks .................................. 213 7.7 Variables ............................................................................................................ 213 7.7.1 Environment Variables ................................................................. 215 7.7.2 Predefined Environment Variables ........................................... 215 7.8 Bash Scripts ...................................................................................................... 217 7.8.1 Example 1: grepall .......................................................................... 217 7.8.2 Example 2: stripcomments ......................................................... 219 7.8.3 Example 3: applysedfile ............................................................... 219 7.8.4 Example 4: Backup Script ............................................................ 220 7.8.5 Example 5: Creating Thumbnails .............................................. 221 7.8.6 Example 6: Setting Up Student Accounts .............................. 222 7.8.7 Example 7: Changing Multiple MySQL/MariaDB Databases ......................................................................................... 223 7.9 Basic Rules for Bash Scripts ....................................................................... 223 7.10 Variables in Bash Scripts ............................................................................ 225 7.10.1 The Scope of Variables .................................................................. 225 7.10.2 Variables Predefined by the Shell ............................................. 226 7.10.3 Arrays .................................................................................................. 227 7.10.4 Parameter Substitution ................................................................ 228 7.10.5 Read Variables Using "read" ........................................................ 230 7.11 Branches, Loops, and Functions .............................................................. 230 7.11.1 If Branches ........................................................................................ 231 7.11.2 Formulating Conditions ............................................................... 231 7.11.3 Case Branches .................................................................................. 233 7.11.4 For Loops ............................................................................................ 233 7.11.5 While Loops ...................................................................................... 235 7.11.6 Until Loops ........................................................................................ 236 7.11.7 Functions ........................................................................................... 236 7.11.8 Heredoc Syntax ............................................................................... 237 7.12 Important Special Characters in Bash: Quick Reference .............. 237 8 Zsh (Shell) 241 8.1 Installation and Configuration ................................................................ 242 8.2 Usage .................................................................................................................. 247 8.3 Oh My Zsh ......................................................................................................... 25011

Contents9 Files and Directories 253 9.1 Handling Files and Directories ................................................................. 253 9.1.1 Directories ......................................................................................... 254 9.1.2 Elementary Commands for Editing Files and Directories ......................................................................................... 255 9.1.3 Determining Space Requirements of Files and Directories ......................................................................................... 258 9.1.4 Wildcard Characters ....................................................................... 259 9.1.5 Complications with Using Wildcard Characters .................. 261 9.1.6 Hidden Files and Directories ....................................................... 262 9.1.7 Special Types of Files (Links, Devices, and the Like) ............. 263 9.2 Links ..................................................................................................................... 264 9.3 Finding Files (find, grep, and locate Commands) ............................ 266 9.3.1 which and whereis ......................................................................... 266 9.3.2 locate ................................................................................................... 267 9.3.3 find and grep .................................................................................... 268 9.4 Greater Convenience with Modern Commands ............................... 271 9.5 Access Rights, Users, and Group Membership .................................. 273 9.5.1 Access Rights for Files .................................................................... 274 9.5.2 Access Rights for Directories ....................................................... 276 9.6 Special Bits and the umask Setting ........................................................ 279 9.6.1 Setuid, Setgid, and Sticky Bit ....................................................... 279 9.6.2 Owner and Group of New Files .................................................. 282 9.6.3 Access Bits of New Files (umask) ............................................... 283 9.7 Access Control Lists and Extended Attributes ................................... 285 9.7.1 Access Control Lists ........................................................................ 286 9.7.2 Extended Attributes ....................................................................... 288 9.7.3 Capabilities ....................................................................................... 289 9.8 The Linux Directory Structure ................................................................... 289 9.9 Device Files ........................................................................................................ 293 10 Process Management 297 10.1 Starting, Managing, and Stopping Processes .................................... 297 10.1.1 Launching Programs ...................................................................... 298 10.1.2 Foreground and Background Processes .................................. 29812

Contents10.1.3 List of All Running Processes (ps and top) .............................. 299 10.1.4 Process Hierarchy ........................................................................... 302 10.1.5 Terminating Processes by Force (kill and xkill) ..................... 303 10.1.6 Distribution of Compute Time (nice, renice, and ionice) .... 304 10.1.7 Input and Output Redirection and Pipes ................................ 305 10.2 Running Processes under a Different Identity (su) ......................... 305 10.2.1 The su Command ........................................................................... 306 10.3 Running Processes under a Different Identity (sudo) ................... 307 10.3.1 sudo with Ubuntu .......................................................................... 309 10.3.2 sudo with Raspberry Pi OS ........................................................... 310 10.3.3 sudo with Debian ........................................................................... 311 10.3.4 sudo for RHEL and Fedora ............................................................ 311 10.3.5 sudo with SUSE ............................................................................... 311 10.4 Running Processes under a Different Identity (PolicyKit) ........... 312 10.5 System Processes (Daemons) ................................................................... 315 10.5.1 Kernel Threads ................................................................................. 316 10.5.2 Starting and Stopping System Services .................................. 317 10.6 Starting Processes Automatically (Cron) ............................................. 318 10.6.1 /etc/cron.hourly, .daily, .weekly, and .monthly .................... 320 10.6.2 Anacron .............................................................................................. 322 10.7 Starting Processes Automatically (systemd Timer) ........................ 323 11 Network Tools 329 11.1 Determining the Network Status ........................................................... 329 11.2 Working on Other Computers (SSH) ..................................................... 334 11.2.1 Copying Files Securely Using scp ............................................... 338 11.2.2 SSH Tunnel ........................................................................................ 339 11.2.3 SSH File System ............................................................................... 340 11.2.4 telnet .................................................................................................. 340 11.3 Transferring Files (FTP and Others) ........................................................ 341 11.3.1 SFTP (Secure FTP) ............................................................................ 342 11.3.2 wget .................................................................................................... 343 11.3.3 curl ....................................................................................................... 344 11.3.4 lftp ....................................................................................................... 344 11.3.5 rsync, mirror, and sitecopy .......................................................... 345 11.4 Lynx ...................................................................................................................... 346 11.5 Mutt ..................................................................................................................... 34613

ContentsPART IV Text and Code Editors 12 Vim 351 12.1 Quick Start ......................................................................................................... 352 12.1.1 Help ..................................................................................................... 354 12.2 Cursor Movement .......................................................................................... 355 12.3 Editing Text ....................................................................................................... 356 12.4 Search and Replace ........................................................................................ 360 12.5 Editing Multiple Files Simultaneously .................................................. 361 12.6 Internal Details ................................................................................................ 363 12.7 Tips and Tricks ................................................................................................. 366 13 Emacs 369 13.1 Quick Start ......................................................................................................... 369 13.1.1 Loading and Saving Texts and Exiting the Program ........... 370 13.1.2 Online Help ....................................................................................... 371 13.1.3 Editing Modes .................................................................................. 372 13.1.4 Keyboard ............................................................................................ 372 13.2 Cursor Movement .......................................................................................... 373 13.3 Editing Text ....................................................................................................... 374 13.3.1 Tabs ..................................................................................................... 376 13.3.2 Indenting and Outdenting Text Manually ............................. 376 13.3.3 Continuous Text .............................................................................. 378 13.4 Search and Replace ........................................................................................ 379 13.4.1 Searching for Patterns (with Regular Expressions) ............. 380 13.4.2 Search and Replace ......................................................................... 381 13.5 Buffers and Windows ................................................................................... 382 13.6 Special Editing Modes .................................................................................. 384 13.7 Configuration ................................................................................................... 386 13.7.1 Setting the Font ............................................................................... 386 13.7.2 Configuration at the Click of a Mouse ..................................... 386 13.7.3 Manual Configuration Directly in .emacs ............................... 387 13.7.4 MELPA ................................................................................................. 38814

ContentsPART V System Configuration and Administration 14 Basic Configuration 391 14.1 Introduction ..................................................................................................... 391 14.2 Configuration of the Text Consoles ...................................................... 395 14.2.1 Keyboard Layout ............................................................................. 395 14.2.2 Font ..................................................................................................... 397 14.3 Date and Time ................................................................................................. 397 14.4 Synchronizing Date and Time via NTP ................................................. 399 14.4.1 The systemd-timesyncd Process (Debian, Raspberry Pi OS, and Ubuntu) .................................................... 400 14.4.2 Chrony (Fedora, RHEL, and SUSE) .............................................. 400 14.5 Users, Groups, and Passwords ................................................................. 401 14.5.1 User Management ......................................................................... 404 14.5.2 Group Management ...................................................................... 405 14.5.3 Passwords ......................................................................................... 407 14.5.4 Interaction of the Configuration Files ..................................... 411 14.5.5 Network User Management ....................................................... 412 14.6 PAM, NSS, and Nscd ..................................................................................... 412 14.6.1 PAM ..................................................................................................... 413 14.6.2 Name Service Switch ..................................................................... 416 14.6.3 Name Service Caching Daemon ................................................ 417 14.6.4 System Security Services Daemon ............................................ 418 14.7 Language Setting, Internationalization, and Unicode ................. 418 14.7.1 Setting the Localization and Character Set ........................... 419 14.7.2 “Cannot Set/Change Locale” Error Message ......................... 423 14.8 Hardware Reference ..................................................................................... 423 14.8.1 CPU and Memory ............................................................................ 425 14.8.2 Power Management ...................................................................... 425 14.8.3 Interfaces and Bus Systems ........................................................ 426 14.8.4 Bluetooth .......................................................................................... 427 14.8.5 Hotplug System .............................................................................. 430 14.8.6 Audio System ................................................................................... 432 14.9 CPU Tuning ....................................................................................................... 434 14.9.1 Controlling the CPU Frequency .................................................. 435 14.9.2 Monitoring the CPU Temperature ............................................ 437 14.10 Notebook Optimization ............................................................................. 438 14.10.1 powertop ........................................................................................... 43815

Contents14.10.2 TLP ........................................................................................................ 440 14.10.3 Controlling the Battery-Charging Behavior ........................... 442 14.10.4 Fan Control ........................................................................................ 443 14.11 Printing System (CUPS) ................................................................................ 444 14.11.1 Sequence of the Printing Process .............................................. 445 14.11.2 Internal Details of CUPS ................................................................ 447 14.11.3 CUPS Web Interface ....................................................................... 449 14.11.4 Administrating CUPS Using Commands ................................. 450 14.12 Logging (Syslog) .............................................................................................. 452 14.12.1 rsyslogd .............................................................................................. 452 14.12.2 Kernel Logging ................................................................................. 455 14.12.3 System Startup Log ........................................................................ 456 14.12.4 Logrotate ............................................................................................ 456 14.12.5 Logwatch ........................................................................................... 457 14.13 Logging (Journal) ............................................................................................ 460 14.13.1 journalctl ............................................................................................ 461 14.13.2 Configuration ................................................................................... 462 14.14 Cockpit ................................................................................................................ 463 14.14.1 Installation ........................................................................................ 464 14.14.2 Security Concerns ........................................................................... 465 14.14.3 Configuration ................................................................................... 465 14.14.4 Operation ........................................................................................... 466 15 Network Configuration 469 15.1 NetworkManager ........................................................................................... 469 15.1.1 Configuration ................................................................................... 470 15.1.2 Virtual Private Networks .............................................................. 473 15.1.3 Proxy Configuration ....................................................................... 474 15.1.4 Configuring NetworkManager in Text Mode ........................ 475 15.1.5 Internal Details ................................................................................ 476 15.2 Manual LAN and Wi-Fi Configuration ................................................... 478 15.2.1 Activating the LAN Controller Manually ................................. 478 15.2.2 Retrieving DHCP Information ..................................................... 482 15.2.3 IPv6 Configuration .......................................................................... 482 15.2.4 Manual Control of the Wi-Fi Controller ................................... 484 15.2.5 Encrypting the Wireless Network .............................................. 485 15.3 LAN Configuration Files ............................................................................... 487 15.3.1 Basic Configuration ........................................................................ 48716

Contents15.3.2 DNS Configuration (resolv.conf) ............................................... 489 15.3.3 Host Name ........................................................................................ 490 15.3.4 Mappings between Controllers and Network Interfaces ........................................................................ 491 15.4 Distribution-Specific Configuration Files ............................................ 491 15.4.1 RHEL and Fedora (NetworkManager) .................................... 492 15.4.2 Debian ................................................................................................ 495 15.4.3 SUSE .................................................................................................... 498 15.4.4 Ubuntu ............................................................................................... 499 15.4.5 networkd (systemd) ....................................................................... 501 15.5 Zeroconf and Avahi ....................................................................................... 502 16 Software and Package Management 505 16.1 Introduction ..................................................................................................... 505 16.1.1 Disadvantages of Linux Package Management ................... 507 16.1.2 New Concepts .................................................................................. 508 16.2 RPM Package Management ...................................................................... 509 16.2.1 Basic Principles ................................................................................ 510 16.2.2 The rpm Command ........................................................................ 511 16.3 DNF ....................................................................................................................... 513 16.3.1 Concept .............................................................................................. 513 16.3.2 Configuration .................................................................................. 514 16.3.3 Searching, Installing, and Updating Packages ...................... 516 16.3.4 AppStream ........................................................................................ 518 16.3.5 Additional Functions ..................................................................... 520 16.4 ZYpp ..................................................................................................................... 521 16.4.1 The zypper Command ................................................................... 522 16.5 Debian Package Management (dpkg) .................................................. 524 16.5.1 The dpkg Command ...................................................................... 525 16.6 APT ....................................................................................................................... 527 16.6.1 Configuration .................................................................................. 528 16.6.2 apt Command .................................................................................. 530 16.6.3 The apt-get Command ................................................................. 532 16.6.4 Additional APT Commands ......................................................... 532 16.6.5 Automating Updates ..................................................................... 533 16.6.6 Synaptic ............................................................................................. 53517

Contents16.7 Pacman ............................................................................................................... 537 16.8 PackageKit ......................................................................................................... 540 16.9 Firmware, BIOS, and EFI Updates ............................................................ 541 16.9.1 fwupd and fwupdmgr ................................................................... 542 16.9.2 Internal Details of Microcode Updates .................................... 544 16.10 Managing Parallel Installations (Alternatives) ................................. 545 16.11 Flatpak and Snap ............................................................................................ 547 16.11.1 Flatpak ................................................................................................ 549 16.11.2 Snap ..................................................................................................... 550 16.11.3 AppImages ........................................................................................ 552 16.12 Distribution-Specific Characteristics ..................................................... 554 16.12.1 Debian ................................................................................................. 554 16.12.2 Fedora ................................................................................................. 556 16.12.3 openSUSE ........................................................................................... 557 16.12.4 RHEL and Clones .............................................................................. 559 16.12.5 Ubuntu ............................................................................................... 562 17 Graphics System 567 17.1 Basic Principles ................................................................................................ 567 17.1.1 The X Window System .................................................................. 568 17.1.2 Wayland ............................................................................................. 569 17.1.3 Wayland Limitations Compared to X ....................................... 570 17.1.4 Glossary .............................................................................................. 571 17.2 Graphics Drivers .............................................................................................. 572 17.2.1 Drivers for AMD, Intel, and NVIDIA ........................................... 573 17.2.2 Problems of Nonfree Drivers ....................................................... 575 17.3 NVIDIA Driver Installation .......................................................................... 576 17.3.1 Operation and Configuration ..................................................... 578 17.4 Determining the Status of the Graphics System ............................. 582 17.5 Starting the Graphics System ................................................................... 586 17.5.1 Wayland or X? .................................................................................. 586 17.5.2 The Role of the Display Manager ............................................... 587 17.5.3 Configuring the Display Manager ............................................. 588 17.5.4 Automatic Login .............................................................................. 588 17.5.5 Monitor Configuration for gdm ................................................. 58918

Contents18 File System Administration 591 18.1 How Everything Is Connected .................................................................. 593 18.2 Formatting and Using USB Media .......................................................... 594 18.2.1 Formatting a USB Flash Drive or SD Card ............................... 595 18.2.2 Mounting USB Media Manually ................................................ 596 18.2.3 Mounting an External Hard Disk Automatically .................. 596 18.3 Device Names for Hard Disks and Other Data Media ................... 598 18.4 Partitioning the Hard Disk or SSD .......................................................... 603 18.4.1 MBR or GPT? ..................................................................................... 604 18.4.2 Basic Rules ........................................................................................ 604 18.5 The parted Command .................................................................................. 605 18.5.1 Example 1 (MBR) ............................................................................. 608 18.5.2 Example 2 (GPT) .............................................................................. 609 18.6 Partitioning Tools with a Graphical User Interface ........................ 610 18.7 File System Types ........................................................................................... 611 18.8 mount, umount, and /etc/fstab ............................................................. 616 18.8.1 Determining the Current State of the File System .............. 616 18.8.2 Mounting and Unmounting File Systems Manually (mount and umount) ..................................................................................... 617 18.8.3 Mounting File Systems Automatically (/etc/fstab) ............ 619 18.8.4 The Syntax in /etc/fstab .............................................................. 619 18.8.5 Bind Mounts ..................................................................................... 623 18.8.6 Automatic Mounts without /etc/fstab ................................... 624 18.9 Basic Principles of File Systems ............................................................... 625 18.10 The ext File System (ext2, ext3, and ext4) ......................................... 627 18.10.1 Administration ................................................................................ 628 18.11 The btrfs File System .................................................................................... 630 18.11.1 Administration ................................................................................ 632 18.11.2 Deactivating Copy-On-Write ...................................................... 633 18.11.3 Compressing Files .......................................................................... 634 18.11.4 Subvolumes ...................................................................................... 635 18.11.5 Snapshots .......................................................................................... 636 18.11.6 Distributing btrfs File Systems across Multiple Devices (RAID) .................................................................................. 638 18.11.7 Determining the Use of a btrfs File System (df) ................... 640 18.11.8 btrfs Configuration in openSUSE .............................................. 642 18.11.9 btrfs Configuration in Fedora ..................................................... 64519

Contents18.12 The xfs File System ........................................................................................ 646 18.13 Windows File Systems (vfat and ntfs) .................................................. 647 18.13.1 The VFAT File System ..................................................................... 649 18.13.2 The NTFS File System ..................................................................... 650 18.14 Swap Partitions and Files ........................................................................... 651 18.15 RAID ...................................................................................................................... 654 18.15.1 Manual Configuration Using mdadm ...................................... 656 18.15.2 Administration ................................................................................. 658 18.15.3 Replacing a Defective RAID-1 Hard Disk ................................. 663 18.16 Logical Volume Manager ............................................................................ 665 18.17 Self-Monitoring, Analysis, and Reporting Technology ................. 670 18.18 SSD TRIM ............................................................................................................ 675 18.19 Encryption ......................................................................................................... 676 18.19.1 Encrypt Individual Files ................................................................. 676 18.19.2 Encrypting a File System ............................................................... 677 18.19.3 Encrypting the Entire System ..................................................... 682 18.19.4 Emergency Plan ............................................................................... 684 19 Grand Unified Bootloader 687 19.1 Basic Principles of GRUB ............................................................................. 687 19.1.1 EFI System Startup .......................................................................... 687 19.1.2 UEFI Secure Boot ............................................................................. 690 19.1.3 BIOS System Boot ............................................................................ 691 19.1.4 The initrd Files .................................................................................. 692 19.1.5 The Future of the Boot Process ................................................... 694 19.2 Operating GRUB (User View) .................................................................... 695 19.3 GRUB Configuration ..................................................................................... 696 19.3.1 Automatic Generation of grub.cfg ............................................ 700 19.3.2 Syntax and Internal Details ......................................................... 701 19.3.3 GRUB Menu Items .......................................................................... 702 19.4 Manual GRUB Installation and First Aid .............................................. 704 19.4.1 Manual Installation and First Aid for EFI PCs ......................... 704 19.4.2 Changing EFI Boot Entries and Settings (efibootmgr) ........ 706 19.5 systemd-boot ................................................................................................... 707 19.5.1 Operation ........................................................................................... 709 19.5.2 Configuration ................................................................................... 70920

Contents20 The Init System 711 20.1 systemd .............................................................................................................. 711 20.1.1 Administration ................................................................................ 713 20.1.2 Targets ............................................................................................... 714 20.1.3 Configuration .................................................................................. 716 20.1.4 systemd at User Level ................................................................... 718 20.1.5 Additional Functions ..................................................................... 719 20.1.6 Compatibility ................................................................................... 720 20.1.7 Documentation ............................................................................... 721 20.2 Custom systemd Services ........................................................................... 721 20.2.1 Custom systemd Configuration File ........................................ 721 20.2.2 Example 1: Setting up Docker Containers as a Service ...... 723 20.2.3 Example 2: Logging the Computer Startup and Shutdown .......................................................................................... 724 20.3 Shutdown, Reboot, and Halt .................................................................... 725 20.4 The Traditional Init-V System .................................................................. 726 20.4.1 Runlevel ............................................................................................. 727 20.4.2 Init-V Scripts ..................................................................................... 727 20.4.3 Links in the Runlevel Directories ............................................... 728 20.5 System Startup on Fedora and RHEL ..................................................... 729 20.6 System Startup on Debian, Raspberry Pi OS, and Ubuntu .......... 730 20.6.1 Raspberry Pi OS ............................................................................... 731 20.7 System Startup on SUSE/openSUSE ...................................................... 732 21 Kernel and Modules 735 21.1 Kernel Modules ............................................................................................... 736 21.1.1 Commands for Module Management .................................... 737 21.1.2 Module Configuration .................................................................. 739 21.1.3 modprobe Syntax ........................................................................... 741 21.2 Compiling Kernel Modules Yourself ..................................................... 742 21.2.1 Automating Module Updates .................................................... 743 21.3 Configuring and Compiling the Kernel Yourself ............................. 745 21.3.1 Basic Principles ................................................................................ 747 21.3.2 Installing the Kernel Code ........................................................... 748 21.3.3 Using Supplied Kernel Configuration Files ............................ 75021